Quantitative criteria for the estimation of the effectiveness of bioluminescence expression in natural and transgenic luminescent bacteria

Computation coefficients for estimating the effectiveness of bioluminescence expression in natural luminescent bacteria P. leiognathi 54 and transgenic strain E. coli Z905/pPHL7 bearing lux-operon in multicopy plasmid are suggested, and their use on the molecular, cell, and population levels was considered. It was shown that, on the population level, all transgenic variants got the better of natural variants of P. leiognathi 54 irrespective of the type of lux-operon regulation. On the cell level, in the bright and dim variants of the transgenic strain, the effectiveness of bioluminescence expression increases by several orders. On the level of one lux-operon, the effectiveness of expression of the bright variant of transgenic strain is substantially higher than in the natural bright variant; in dim variants, the efficiency values are similar, and the effectiveness of bioluminescence expression in the dark variant of E. coli Z905-2 /pPHL7 is by two orders lower than that in the dark variant of P. leiognathi 54.     

Quantal Characteristics of Synaptic GABA Release under Conditions of Stimulation of Single Synaptic Terminals of Cultured Cortical Cells of the Rat

We studied evoked inhibitory postsynaptic currents (eIPSC) using local electrical stimulation of single presynaptic terminals of cultured rat neocortical neurons. According to pharmacological and kinetic properties, these currents were qualified as GABA_A-activated. Using autocorrelation analysis of distributions of the eIPSC amplitudes, which were in all cases polymodal, we examined quantal characteristics of the above eIPSC. These results were compared with the values of quantal parameters (N, p, Q, and m) of the current families obtained using approximation by binomial distribution. Amplitude histograms of spontaneous miniature IPSC recorded under conditions of the minimum quantal release of the neurotransmitter were normal (close to Gaussian) with the mode within a 10 pA range, which is very close to analogous parameters calculated using autocorrelation and binomial techniques.     

Some Neurophysiological Correlates of Altered Mental States in Labor: Report II. Features of the Superslow Phasic Processes

A group of parturient women (n= 45) was divided into subgroups of subjects with a large and small number of signs of an altered mental state (AMS and NAMS, respectively) during and after labor, according to data of a special psychological questionnaire. The background EEG and the superslow phasic electric processes (SSPP) of the head surface were recorded simultaneously in 16 monopolar leads before and after labor. The parameters of autocorrelation and cross-correlation functions of the processes were calculated. Highly significant differences were found among the subgroups in the parameters of dynamics and spatial synchronization of the SSPP, related, in particular, to the activity of the anterofrontal zones of both hemispheres and of the temporal zones of the right hemisphere. The differences between the AMS and NAMS subgroups were revealed on the basis of the different extents of the unidirectional deviations from the SSPP parameters in the reference group of healthy nulliparous women. The pattern of interrelations of the investigated parameters of the EEG and the SSPP confirms the hypothesis that functional changes in the brain during the adaptation of women to pregnancy termination and physiological labor correlate with a special mental state.     

The Content of Peripheral and Integral Proteins in Vertebrate Brain Microsomal Membranes

The content of peripheral and integral proteins in brain microsomal membranes in 11 species of vertebrates is studied. The amount of peripheral proteins does not exceed one third of the total protein, whereas integral proteins account for the main mass of proteins of microsomal membranes in the brain of animals at all levels of the vertebrate organization. Predominance of integral proteins can be considered as an indicator of a significant rigidity, high stability of brain membranes, and predominance in neuronal membranes of complex receptor proteins, ion channels and pumps, as well as ion exchangers. Microsomal membranes in the brain of reptiles are characterized by a higher content of peripheral and integral Triton-soluble proteins in comparison with other classes of animals. The possibility to use data on chemical composition of the brain microsomal membranes for study of congener relationships of vertebrates is considered.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 2, 2005, pp. 125–128.Original Russian Text Copyright © 2005 by Medvedeva.     

Catalytic Properties of Cytoplasmic and Mitochondrial Aconitate Hydratase from Rat Cardiomyocytes

Enzymatic activity of aconitate hydratase (aconitase, EC 4.2.1.3) from the rat heart is localized in the cytoplasm (65%) and mitochondria (35%). Cytoplasmic and mitochondrial forms of aconitate hydratase were separated by ion-exchange chromatography on CM-Cellulose and CM-Sephadex. The two forms have similar molecular weight, optimal pH range, and spectral properties; however, they have different chromatography properties, K _m for citrate and isocitrate, as well as sensitivity to Fe²⁺ ions.     

Detergent properties of apolipoprotein A1 in micellar complexes with dimyristoyl phosphatidylcholine

Bilayer micellar complexes of the human plasma apolipoprotein A1 with dimyristoyl phosphatidylcholine were prepared under kinetically controlled conditions. Detergent-like properties of Apo A1 in the complexes were expressed in terms of delta SA1 parameter (surface area of mixed micelle per an Apo A1 molecule). Analysis of our and earlier published data showed the correlation of the delta SA1 parameter with the stoichiometry of complexes. Changes of detergent-like properties were caused by cross-linking or proteolysis of Apo A1.